The present invention relates to the structure of the door of a microwave oven.
The conventional structure of the door of a microwave oven is shown in FIG. 2. Typically, a microwave oven is installed by correctly aligning the edge of the opening of the housing sheet 1 with the externally bent edge portion of the opening of the cooking chamber 3, followed by setting the magnetron 2 which is installed in the space between the upper surface of the cooking chamber 3 and the housing sheet 1 for radiating microwaves into the cooking chamber 3. A heat-resistant plate 4 accommodating food 5 is installed on the bottom of the cooking chamber 3, and a door A is installed in the front opening of the cooking chamber 3, i.e., oven B, so that the door A can be opened and closed freely.
The structure of the contact part of the door A and the front portion of the cooking chamber 3 is described below. As shown in FIG. 3, the door unit 7 has an edge yoke which is sectionally free of a slit, while the fixing plate 8 is secured to the inner edge yoke. A shielding plate 11 is sandwiched between the fixing plate 8 and the inner door plate 10 by securely being fastened with screw 12. The inner transparent material 9 adjacent to the shielding plate 11 is sandwiched by the edge yoke of the inner door plate 10. The choke cover 13 is placed between the edge of the external angle of the inner door plate 10 and the other edge of the external angle of the door body 7, thus forming an empty choke cavity 6 along the external edge portion of the door unit, while the choke cavity 6 is tightly held against the edge of the opening of the cooking chamber 3 to prevent microwaves from leaking outside. The periphery of the door body 7 is provided with the holder plate 15 of the front screen which is tightly pressed against the front surface of the door body 7, while the holder plate 15 is fastened with screw 17. Using the edge yoke, the periphery of the holder plate 15 is covered so that the head of screw 17 can be concealed. As is clear from the structure mentioned above, a conventional choke cavity provided in the external periphery of the door body needs to use a variety of parts, including a holder plate 15, edge yoke 16, inner door plate 10, fixing plate 8, screws 12 and 17, etc., all of which are fastened with screws before eventually being assembled into a complete door unit. As a result, the door unit requires a number of parts, thus unavoidably causing the assembly process to become complex, lowering productivity and raising costs.